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|MainCategory=Microbiology | |MainCategory=Microbiology | ||
|SubCategory=Infectious Disease | |SubCategory=Infectious Disease | ||
|Prompt=A 3 year old boy is brought to your office after her mother noticed that he has had watery, nonbloody diarrhea for the past 2 days. The mother reports that several of her | |Prompt=A 3-year-old boy is brought to your office after her mother noticed that he has had watery, nonbloody diarrhea for the past 2 days. The mother reports that several of her son's playmates from daycare have had similar symptoms as well. Which of the following describes the most likely causal organism? | ||
|Explanation= | |Explanation=Rotavirus is the most common cause of diarrhea in children. It is particularly prevalent in places where many children come in contact with each other such as daycare centers. Rotavirus causes diarrhea because sloughing off of intestinal mucosa leads to poor absorption of water and Na+. The infection typically lasts a few days before recovery. Residual lactose intolerance as a result of epithelial degeneration can take longer though. Rotavirus is a nonenveloped dsRNA virus with icosahedral capsid symmetry of the reovirus family. | ||
|AnswerA=ssDNA virus | |AnswerA=ssDNA virus | ||
|AnswerAExp= | |AnswerAExp=The parvovirus family is composed of ssDNA viruses. Parvovirus B19 is responsible for [[erythema infectiosum]] in children (also known as fifth disease or slapped cheek syndrome). | ||
|AnswerB=dsDNA virus | |AnswerB=dsDNA virus | ||
|AnswerBExp= | |AnswerBExp=The majority of DNA viruses are composed of dsDNA. | ||
|AnswerC=ssRNA virus | |AnswerC=ssRNA virus | ||
|AnswerCExp= | |AnswerCExp=Most RNA viruses, including the Norwalk virus are composed of ssRNA. While the Norwalk virus is a cause of diarrhea in both children and adults, it is not the most common cause of diarrhea in children. | ||
|AnswerD=dsRNA virus | |AnswerD=dsRNA virus | ||
|AnswerDExp= | |AnswerDExp=Rotavirus is the most common cause of diarrhea in children and is a dsRNA virus. | ||
|AnswerE=Bacteria | |AnswerE=Bacteria | ||
|AnswerEExp= | |AnswerEExp=Bacteria are not the most common cause of diarrhea in children. | ||
|EducationalObjectives=Rotavirus is the most common cause of diarrhea in children and is a dsRNA virus. | |||
|References=First Aid 2014 page 162 | |||
First Aid 2012 page 186 | |||
|RightAnswer=D | |RightAnswer=D | ||
|WBRKeyword=Microbiology, Diarrhea, Gastrointestinal, Virus, Viruses, RNA virus, | |||
|Approved=Yes | |Approved=Yes | ||
}} | }} | ||
Revision as of 22:10, 15 March 2014
| Author | PageAuthor::William J Gibson |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Microbiology |
| Sub Category | SubCategory::Infectious Disease |
| Prompt | [[Prompt::A 3-year-old boy is brought to your office after her mother noticed that he has had watery, nonbloody diarrhea for the past 2 days. The mother reports that several of her son's playmates from daycare have had similar symptoms as well. Which of the following describes the most likely causal organism?]] |
| Answer A | AnswerA::ssDNA virus |
| Answer A Explanation | [[AnswerAExp::The parvovirus family is composed of ssDNA viruses. Parvovirus B19 is responsible for erythema infectiosum in children (also known as fifth disease or slapped cheek syndrome).]] |
| Answer B | AnswerB::dsDNA virus |
| Answer B Explanation | AnswerBExp::The majority of DNA viruses are composed of dsDNA. |
| Answer C | AnswerC::ssRNA virus |
| Answer C Explanation | AnswerCExp::Most RNA viruses, including the Norwalk virus are composed of ssRNA. While the Norwalk virus is a cause of diarrhea in both children and adults, it is not the most common cause of diarrhea in children. |
| Answer D | AnswerD::dsRNA virus |
| Answer D Explanation | AnswerDExp::Rotavirus is the most common cause of diarrhea in children and is a dsRNA virus. |
| Answer E | AnswerE::Bacteria |
| Answer E Explanation | AnswerEExp::Bacteria are not the most common cause of diarrhea in children. |
| Right Answer | RightAnswer::D |
| Explanation | [[Explanation::Rotavirus is the most common cause of diarrhea in children. It is particularly prevalent in places where many children come in contact with each other such as daycare centers. Rotavirus causes diarrhea because sloughing off of intestinal mucosa leads to poor absorption of water and Na+. The infection typically lasts a few days before recovery. Residual lactose intolerance as a result of epithelial degeneration can take longer though. Rotavirus is a nonenveloped dsRNA virus with icosahedral capsid symmetry of the reovirus family. Educational Objective: Rotavirus is the most common cause of diarrhea in children and is a dsRNA virus. First Aid 2012 page 186]] |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Microbiology, WBRKeyword::Diarrhea, WBRKeyword::Gastrointestinal, WBRKeyword::Virus, WBRKeyword::Viruses, WBRKeyword::RNA virus |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |